Optical fibers typically have a glass core and cladding and two coatings. The coating's function is two-fold: to protect the optical fiber from mechanical damage and to preserve the ability of the optical fiber to transport light. The primary coating is applied directly to the glass core and cladding, it is typically a low modulus soft, cushioning material. The secondary coating is applied over the primary coating and is typically a high modulus material that functions as a tough protective layer that protects the fiber from environmental exposure and mechanical damage.
Optical fiber has acquired an increasingly important role in the field of telecommunications, frequently replacing existing copper wires. This trend has had a significant impact in all areas of telecommunications, greatly increasing the amount of data that is transmitted. Further increase in the use of optical fiber is foreseen, especially in metro and fiber-to-the-home applications, as local fiber networks are pushed to deliver an ever-increasing volume of audio, video, and data signals to residential and commercial customers.
As the demand for optical fibers has increased, so has the desire to improve the processes used to make them. One common trend in the optical fiber industry has been the desire to draw optical fibers at increased speeds, thereby increasing the throughput of optical fiber manufacturing plants. However, the draw speed can be rate-limited by the step of curing the conventional polymeric coatings used to protect the fiber. One sign that a coating is applied to an optical fiber at a rate exceeding the coating's maximum draw speed is the presence of defects in the cured coating. There remains a need for optical fiber coatings that can be fully cured at higher draw speeds using standard optical fiber coating curing processes.